This invention relates to a compact size travelling mechanism utilizing ultrasonic wave motor so as to travel into places as narrow as where human hands cannot enter, such as a small and narrow pipe.
As shown in FIG. 4 a sectional view and FIG. 5 a front view of a known electro-magnetic type travelling mechanism, a certain voltage from a driving circuit (not shown in thee drawings) is applied to a coil 53, whereby, a coil core 50 is magnetized, and then a tip of the coil core 50a was attracted and repelled to a permanent magnet 51, thereby generating a vibration. By applying this generated vibration to a slanted brush 52 attached to the lower face of the permanent magnet 51, the mechanism can be advanced in a certain direction. FIG. 5 shows a front view that the equipment has two parts, a left-hand as described above and a right-hand part comprised of a coil core center 150, a permanent magnet 151, a slanted brush 152, and a coil 153, which are structured the same as the left-hand part. The two parts are connected in parallel. By controlling the two parts, respectively, the mechanism can change directions.
FIG. 6 and FIG. 7 shows a sectional side view and a front view of a conventional travelling mechanism. A plurality of blades 61 are attached to a shaft 64. A box 60 enclosing the blades 61 is attached to the shaft 64. Driving wheels 63 and 163 are attached to each of the shaft ends 64a exposed from the box 60. From a pipe 62 attached to the box 60, air can be sent to turn the blades 61. Through the shaft 64, a turning force is transmitted to the driving wheels 63 and 163 to advance the mechanism in a certain direction.
An ultrasonic motor is disclosed in U.S. Pat. Nos. 4,533,219 (Katsuma et al), 4,562,374 (Sashida) and 5,006,746 (Kasuga et al).
Known travelling mechanisms had such problems that the coil could not be manufactured any smaller, and that the coil became overheated and damaged by excessive current, or the mechanisms could not be controlled as to their direction of travel.